The present invention refers to improvements in framework for mounting portable arms on vertical members, of the type which comprise some few vertical mountings preferably braced, over the which are disposed some few portable arms horizontal in projection, capable of being immovably fixed at a desired height, the mountings in practice carrying some apertures adapted to interface with support elements disposed on an end of the portable arms.
There are already known mountings which present vertical threads aligned to inclined openings of rectangular form, adapted to receive unique cotter pins formed rectangularly in transverse section. In such cases, the rectangular form of the cotter pin contacts surfaces of the apertures of the mountings which are small enough to give rise to elevated forces above the edges of the openings of the mountings and of the supporting elements which produce deformations.
According to the present invention, a framework is provided for fixedly supporting a horizontal arm at one of a plurality of locations from the vertically extending member. The vertically extending member is provided with a plurality of separated rectangular openings, each of which can be aligned with a similar opening on one end of a horizontal arm. The arm can be locked to the vertically extending member by insertion of a pair of cotter pins of right triangular section through the aligned openings with the hypotenuses of the triangular sections being in contact. The other dimensions of the triangular section are less than the corresponding dimensions of the openings so that after insertion of the pins through the opening, downward movement of the arm misaligns the openings and locks the arms to the member.
Other characteristics and advantages of the improvements in the system of fixation of the movable arms on vertical mountings which are treated will become apparent from the following description taken in relation to the attached drawings which illustrate, by way of example and not of limitation, an embodiment of the present invention.